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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42fa53b8fc4fdc5bb2fee7afd7d3fd6f2a421a77a338476d3a8451f9487bbd33' 
  AND token = 'dteJRoEXMPR6zXarsJGBUHyzBQIHTPpT1YjdfiGAKoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}