SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8119b031372a1f3eb094fd1a71db60d3a7a434c4916f2002eed23a51cd51b6a' 
  AND token = 'oqxPHJ1Yi9z6mH7iqe5xPEKQpUx5QvDXkXxIQwPUdR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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