SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c16731de175d10b719fa587f6cea5e06231d4f9e16e7094764e62e0efb20ec5c' 
  AND token = '+Wki69RWa413k3VnQ5vCi/dZaT0RctRzZBqp+m+ruOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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