SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff16be6c7d64864e22ee74dd5540f37785d6f03c7022949f8f20851da3effc40' 
  AND token = 'toMGioumLKN7rQwIQK8wT8TlEB23fpDV8jm1nnf3rCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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