SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c877a5d36970c35a175aaf78ad0c8a2d6213201140011c4838926616e27a9f58' 
  AND token = 'TmMZJTWdktdHuL3lr9kOQyEUkxlOT87T/IsDPSmyfLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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