SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '185b7b4607262396656b8e8f22f218849098783e2928402c490c624103921762' 
  AND token = 'BIv9ZpsCEBktGvKthVAMvwfk9Sz9sopodt+SrOxQwK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}