SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40999bafaf22de235e7fb77fedc10f017356b1b95bb6ad3572de67b5d00fb767' 
  AND token = 'g8p5XN1++Vwfs90avCbdPwzxUI1pCvIxKccQl/JoF+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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