SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab153bf3cf4248bae7b8175db9036345fe2648fe794f9b76f63db2a8d0f65db7' 
  AND token = 'O08GjVq2nZ2isWY4j7KTLYj540YcVV/Rp0uLxluYpjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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