SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194f0b123dd2adafba8c32e183c28ef82e9854b27ee311b80fe603850de58db9' 
  AND token = 'yHLwjOwGzIJRnVSHp9mOzZ3HzJ23tD+UoXuCY5A8ags=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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