SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '403f2eebc734a61a75f1da3d8206c86b7f24758c1b6b4e08afda4da173f9ad99' 
  AND token = 'HlWtlbVRLwMeEFSt0WPSHfJuP2i3uTy3TbcntQDhQWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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