SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f5ea2b6a178662ea921e744c9ea569264b2820ff3a745f2593d9370e8103db' 
  AND token = 'TVh5XarFSlPKczbA/Wauuj+EIuoHfnuD51xPd+y7OpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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