SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fc76f10152e269b64b1bd88f132474431d447376e29b8c70a852fdcd84c8e3d' 
  AND token = '7Mo0DtllarVEYK9+WK0TDfVNF8/CUGzI0BSXSbvwOoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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