SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c167199c1080d2843c44aea0b52be129256ea01a5d8732c823d63dbd5edad2b' 
  AND token = 'hiQ+aZLv/jRyVwLaDqhyH1bTFmnJiZyPcwizDRCgjVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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