SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28e96136abb71e2127790150aff2109fb6ee4b9e8ce3fdb55beb4da416d9d404' 
  AND token = 'E4gi57FwaTT6L8qmWwhFU7MDZHoEFrpbrw3B2qHAlH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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