SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e2490d334a3650348def728cfa72f047d3fdb438deacd505b4c188fa49f3e73' 
  AND token = 'lR3MfIk7uqmIJ1DpYPsIuGHwhOt/wDEihGv+607YQss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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