SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ce4ac9be8ef47b4f5d1ced2425634af67b88efc347ba011333e06356a0aa3d' 
  AND token = '1gYEEiwK3+sCqdZRiGhpFxXdZAI99/DSZiXHKALVrdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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