SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b90c45abac773adefbce42e72ca8f5cd668485606b174932393a6fbf902b20' 
  AND token = 'wfM3o/k8+dU4k7hSV85cErGqhXmwsJ1QTJDUKftiNEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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