SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8ed551b816b15f741eeea8160102cd43487c1c75ef05c645af49f78d3490564' 
  AND token = 'SkaOqwAPxeBhraM5XYuS8l/ShHz4LlN3ecx4NOvvXFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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