SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b55bfde203e998c1a20ddfb359d42294e831e252c8413891de52e9239a57565' 
  AND token = 'ph+6RaIdBkI2JWs81wkEATeSbk3uyf0kUgMFJysvdaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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