SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef0e84f052b231f19a1bf7424a449a54c946ee7c83cc9e181d1ce697622a6846' 
  AND token = '78n4apJQFxMQm8WXtCjDjnAHTKFVyNtJFGZx82hcdOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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