SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f085cd81ecff1a4ed2ea3cc0ba1df8361de52b74900d010d92dddc6ac9839b6' 
  AND token = 'OB3OPWnv87B6haOwFpi5BVTBrsIpCqKA79lTbd86m+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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