SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '634c7eeb11ab248ab29eb659711562f56a61331b94310af02c2f86657654fb31' 
  AND token = 'OsIQsAbn5rLjgGVcKAKnC8pW0ROvl0/92rJMi17WdAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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