SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '046837a99a22d3afbce7cb54d21083b79afb5d5ee8bfab9f299ce28a7085078b' 
  AND token = 'JawxIOSGuYMdxkHcmedZ1HmOzpMziKjpnI/XmvIszjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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