SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '135c5d82d74f5baa50c8a491df8fa1a7547a0b3c2741e0d747151ef810abce18' 
  AND token = '/7IoZLNo4Uxrhuq8uEGIOijEYRIGeX8TZY0bTEH0tzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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