SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0bb511aa522b08abb3e03364d6e4476dbb23cb751714e9117a4a0e8983a36fe' 
  AND token = 'H/zEGr0+QqXmUBlvzg1+NrkQELiOzRGVbYT+ZMw3HK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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