SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a179eb8d098eb1bbf77d9139534229715842f5e7c815c562334cadd72211c1a' 
  AND token = 'UYCPTnFCSHWMq5G53OZxIfPNeYpZGb9KyLy3HazwQLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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