SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '936beea35e432790fb3ff851303fa05b1c701eb0c4f5a90986cef25caf4b0f1d' 
  AND token = 'MDyBy0wbwSVIZ1AavCfIYGt/Rm0puEA4h3J2IViKjwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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