SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404a7d35905b80b71b4fcf7eea69ac42b42ebce752ddea982819a5879c12027f' 
  AND token = '+t49SPkL3EIKVjbzKmuZdY8H73TqHsbR9elJd/kB1kU=' 
  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"
    }
  }
}