SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a272196b90dbacc121bcae32a7e54424107eb9b33fae745c7d26ca54e69b293' 
  AND token = '9n9HFqXPJq26byn6sCQoQVmDqz3f8iNykDzgptWNIRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}