SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4074d760c27097e93f6511249eb84fa1c63b1ba5fe11f1b595d43aaa25c15029' 
  AND token = 'm9xvT+osidF4rK7Br/QThrYttcgFgAIHuuS0VVg97jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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