SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3392ed6db968d65cb83fb2cbede6807d48dfdce2400d015a97eb8cd383b4e31' 
  AND token = 'IpwtE3Ko5n1rjo9fPpcffsFLzIqqrXh2s56V7LmOP7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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