SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15ffb8f0667024ed1370cc6339f92b009676f29b28a6b841a0fd53a3017bd9bd' 
  AND token = 'DI4sCeLy1JCEkqwmJM4VeqcrIIiBg6LnYKNDsiafSIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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