SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b641c758f00f6413465eb5cc4d9a5318127cae63d15e18e42837b2454ab455c1' 
  AND token = 'Z6Z/p9+fzVOc1Q4QkWHKOheJ9bWzDPgiglzfYNc6Mvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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