SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb94d9b52364042a24590997719900937ef8b5f52432d884df1c36c8b39527a4' 
  AND token = 'XqJs6q/fSOw41HpbBRCpXlgj2UPaDw7NblBTfxZNI3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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