SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3a205e60a82ebdca10711397de56a43dfb4764ef141602d8930bad5bbdd8b4a' 
  AND token = 'QIlmKlKo5GNDXZ8xVYX2ItqVJlLRCUDX+nCM/3XvAkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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