SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c41b25d6ba877b571f08d41fc5e03070987e245699233af89ff87718367b3a' 
  AND token = 'VbiotbAQJ9dq7/5Ne6SqVNiV+KvJCtIwCQgozPyySBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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