SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '764419e1ac824981d7a0c01b583f0c386b13e510eff88e8fcd48464e1269546d' 
  AND token = 'sNwZurORDaAiXJZLbhGwn0TKjvPrAKdlXU5REBcfiao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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