SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bbe75fe1a16b04b4f45a065755175168fe096c267dac84aac946f91dc74d7fa' 
  AND token = '1kv2PGHfn4ISIJSK8Vn0ZFOX1YHYKiitBJJzxldE2Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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