SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d9303189bbb7595893c96e19fe6ae0887bb9c682c2601729f2aba522684936e' 
  AND token = '4gm+0iT4saZPcPS9oU6I6QCRDOjEq5bdLBsVkSE6fQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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