SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86ca512f67ddf4e380c96f86008bf3963fef46696f0438238c93a90e7f9e5bcc' 
  AND token = 'L2RTnbY/1+q68PeoaC9UwGPo3oBpKWXYjZrfrgZPfvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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