SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '664da2b697d990515cea4d153888beca741f2f9644685e5ad13af06730a2533e' 
  AND token = 'UkNU//jB4CmMNFuzeBZC48skc7hjx1GhSwt+Yc3PkIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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