SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16e579f63e2ec583e6347b0a0c12694f119e198dd9acb4689e31030bf53306d5' 
  AND token = '92PJrbCaST/vgEt3k+wT7KqfOfXj4gKBQ0ymGOcOB1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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