SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd3100fb475d8f00d635870916310cbe5d1ae666f0bb7fb7838d13fea98cac026' 
  AND token = 'lhl1BssTwFmIAkbCZdMd06HVkzpvmHp6k0aNkvUy/F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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