SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7932ff0fc9d69dca8a0bdaa72770d1791696f57608652812f3f4e88290c9e488' 
  AND token = 'UABn1Y6RmjrX6f0DvQk7MXzJRvjWWvdQkoDcXq4+GR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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