SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca6b52ca086ca49ac3592e61f01742debacd30be815ed658d3d8b204ec8dddcf' 
  AND token = 'viNoJo28nFes8tyzNSOQGsxHR2nVYBv2YDbKD1Lprpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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