SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9bf88d97e3c60f8723714359843259e06dc83d92803776b12aa438cb92f8d73' 
  AND token = 'ghLfrBDHB3bRtYNYgkeIB+eHpcA6ZP4UsugetVE3QGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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