SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fa6259b9df8c62fec5f05bbf8e9cfc3794cbd67b8398ba1863644d739948dad' 
  AND token = 'qOZ7NYC3HwaRhZl8qtKNB7LwO2uXwKyvdUbQ1tKlMfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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