SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b78fc45d788153d57ac71bb71b17a0784dfde394bbb00b097f9d44f988e179b' 
  AND token = 'oYkAHZYSAC+NsaknobkuOgmOeipTOkGbCWvOr9Pmy4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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