SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd2717667d53e5104d918f62465a50e3e5709346b7213c68c4bab9b52dd0d312' 
  AND token = 'jrLjUY9NCl0CdBhpAvfSgWSpumGlnfbtj8OqGfVM7lI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}