SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc3c903dcaa497904de831f618b5d7b80e5784140ab5746194c1bf2671a1956d' 
  AND token = 'mE+8EiT3l5dQf1FnV+Cn3To8PZdTyktGP/2EltyK8HU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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