SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8c3e25d131b5d71c9587e89be86918aa5aac77af6acb15ab3fe09241dd574a5' 
  AND token = 'UnQ0HF20skD3/exvHx33afOCrwnlC8k18NCgRw5AzyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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