SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c53fd72a488c3fd2eb46d77986c6a694f29b92a251d6c36a460b9aa534ae38fd' 
  AND token = 'vuJjwm83fZ54rtQtthaVstutEiZK3KBVPVLNseOLCp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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