SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdacf16a1de20a781a155f7572bb602f2cc05b61347597d4399d3ec791b2aabe' 
  AND token = 'QmmkHXCj6CzqqRsc8VjL+e2//fBhh9YjptCDiQW3qKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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