SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44f61892689f1f63a5331f571109fbf6b64e37604e57360f6ef198e70f16d930' 
  AND token = 'OyijxppwRL9Pv7SLpVkrb23dUdWYNpdZmAZt26+yCD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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