SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '416ad2140a609da4352ec6926df388dc9ca3209f6d76c33c59cd2b8ed55b4555' 
  AND token = 'UyhYjfD8e+S8Po1AoLQseJdaqrHhlcWvR8+BbWnqO/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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