SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb7654a7779684ebbd80f0fe67aaa836c03ec85fef4902ca45ecfd69199c365' 
  AND token = '5qSNXjzakTCQ6R/W4b7vZHtZdkLcq9deYhw+iPVfe1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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