SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea26545ce818243312b5d4162846918862af1531bbab2ffe5a675be734b3192a' 
  AND token = 'lPjAWBZnAXNnf93CZkkcragdt/pbWt6YG3teO8IvMUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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