SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4a768f0fde3917511612e31c475f708b60fa317c1415c17d20815a60781905d0' 
  AND token = 'GFQSRSIhjKz5SQ4rTyKmdNWTlAS0Aw3A0Jt91TrnAPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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