SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6383fa1e0473d2f7281e84dab4029c1c5934835db98403c3d96c02fc87789a12' 
  AND token = '7u+J0RwPG0S1Xggd3hvMEiqITqDaSBFE8vWtLZMQCY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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