SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04ffb83cdefdf357e6d7f81413506bbc13b150e88ebcac9edf3743fbabc48d80' 
  AND token = 'Hd7Dlo7+QppfOPWJW3OEC2KCI9afxcAsdo73WxK9Nr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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