SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6588a7397ffbd62df2635ff51409195d81952a6ef3d203684fa54b7ddb335d3' 
  AND token = 'gR1IHKX9IHQymj8MWQAwoUGC7PmioEL6SbDK/hCKDYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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