SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7a753ac3659cefb17148b3f682feead541cc30d41685cf527d3c087c001e8a8a' 
  AND token = '0iG3DoJpZBXFhZgj5nkTt3CKbMhP1yGTqSSbSX2PPLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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