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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9e548fd491e2e7260b60ac4d8823c3ba76d54ad22c5dd0cd20bab8b7bff3c72' 
  AND token = 'kKcUqXy9vt2OjEaK9Sk4aR0EXuJ8nkJfvInUE/oMZBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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