SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7941d6528a77d93a63e037bd938b860518b63eebef6fe59d7e746547e303c50d' 
  AND token = 'KAXJVe0Esi/ViFV/XUaELV0dRMvyj8lVxRYfuJgDiOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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