SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35e19bb575d236ce62f1458403c7e62c1a72f7c67f76125cd6c57fc8952e2ac2' 
  AND token = '3fl/OSMBSPe5JPjZIxGAQF3RCwmT8npgg5puPcxFvOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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