SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4a456e2bd26f4ccb99fbd72beac35e0888dde4b3c31440f9b24da47ffcea4ad' 
  AND token = '2cjGhxzdSm8U6VutkNbD8aBYsxJw/688S0WdyDVSeqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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