SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dc7ba6aaf8b5c724c9142d37b892afc63d47384e8e2d5346af779e9a12d0a89' 
  AND token = 'p8kBYb3v5sXgEwOhN/TP8xHHW/RRHhL0SUz5JHO+EnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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