SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70847300dcbae98219d69f89df20d46be92b5e479b3034ec3ee9daae588d7a6f' 
  AND token = 'Vr5D7O8lCiBuCjHxfnLyb8f5AppDHSBDG5eVOxuhPfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}