SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b6ccb2b1a3d19d99cdd4aa1a77435cc6713ad91db42b39da026fcf52814de19' 
  AND token = '2lzYxgjk4xI5vOraBA7TKq38C8eOUQd/nmEZaCm30NY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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